UCC35701D UNITRODE, UCC35701D Datasheet - Page 4

• Manufacturer Part Number: UCC35701D
• Description: PWM CONTROLLER, SMD, 35701, SOIC14
• Manufacturer: UNITRODE

Specifications of UCC35701D

• Input Voltage: 11V
• Output Voltage: 1V
• Output Current: 100mA
• Frequency: 700kHz
• Supply Voltage Range: 10V To 13V
• Digital Ic Case Style: SOIC
• No. Of Pins: 14
• Operating Temperature Range: 0°C To +70°C

DETAILED BLOCK DIAGRAM
PIN DESCRIPTIONS
VDD: Power supply pin. A shunt regulator limits supply
voltage to 14V typical at 10mA shunt current.
PGND: Power Ground. Ground return for output driver
and currents.
GND: Analog Ground. Ground return for all other circuits.
This pin must be connected directly to PGND on the
board.
OUT: Gate drive output. Output resistance is 10W maxi-
mum.
VFF: Voltage feedforward pin. This pin connects to the
power supply input voltage through a resistive divider
and provides feedforward compensation over a 0.8V to
3.2V range. A voltage greater than 4.0V or less than
0.6V on this pin initiates a soft stop cycle.
VS CLAMP
COUNT
VFF
ILIM
CT
FB
RT
S S
10
14
9
2
6
7
8
1
I
V
REF
0.6V
0.2V
1.5R
I
RT
0.6V
4V
R
S S DONE
2*I
P WM
CURRENT FAULT
CURRENT LIMIT
RT
0.7V
D
R
HIGH LINE
LOW LINE
Q
0.2V
V
REF
VALLEY
P EAK
I
4V
4
Q
RT: The voltage on this pin mirrors VFF over a 0.8V to
3.2V range. A resistor to ground sets the ramp capacitor
charge current. The resistor value should be between
20k and 200k.
CT: A capacitor to ground provides the oscillator/
feedforward sawtooth waveform. Charge current is 2 ·
I
age. The ramp voltage range is GND to V
Period and oscillator frequency is given by:
RT
R
S
D
, resulting in a CT slope proportional to the input volt-
T
F
25*I
=
»
V
S HUTDOWN
R T CT
R
S
R T
2
LATCH
D
·
Q
2
·
I
0.2V
·
R T
C
T
+
S
R
t
DIS CH
D
RUN
Q
S S DONE
»
0 5 .
LATCH
FAULT
R
S
D
·
P WM
Q
R
T
3 A
·
13/9V (35701)
9.6/8.8V (35702)
C
VDD
5.0V
REF
T
4.5V
RT
UCC15701/2
UCC25701/2
UCC35701/2
.
11
13 GND
UDG-98004
3
4
5
12 VREF
S YNC
P GND
OUT
VDD